The Study of Wrinkling Mechanism of Plasma-Treated Microphase-Separated Polyurethane Surface

2018 ◽  
Vol 773 ◽  
pp. 3-9 ◽  
Author(s):  
Ilya A. Morozov ◽  
Anton Y. Beliaev ◽  
Roman I. Izyumov
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Elastic Modulus ◽  
Finite Element Modeling ◽  
Layer Surface ◽  
Element Modeling ◽  
Compression Deformation ◽  
Good Accordance ◽  
Nitrogen Ions ◽  
External Strain

Stiff coating on the phase-separated soft polyurethane substrate under the compression deformation is investigated by the finite element modeling (FEM). External strain leads to the wrinkling of layer surface, which is characterized by a set of wavelengths and amplitudes. The influence of the thickness and stiffness of the layer, elastic modulus of the substrate on the structural-mechanical properties of the deformed surface is studied. The results of the model are in good accordance with the experiment (plasma immersion ion impanation of nitrogen ions into the polyurethane substrate) and allowed to estimate the modulus of the coating and the deformation of the surface.

Mechanical Evaluation of Hydroxyapatite Nanocomposites Using Finite Element Modeling

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Kristopher Doll ◽  
Ani Ural
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Elastic Modulus ◽  
Aspect Ratio ◽  
Finite Element Modeling ◽  
Graphene Nanosheets ◽  
Bone Implants ◽  
Graphene Nanosheet ◽  
Computational Framework ◽  
Element Modeling

Hydroxyapatite (HA) has been proposed as a candidate material for bone implants because of its similarity to the inorganic phase in bone. However, due to its lower mechanical properties compared to bone, it has not been used in load bearing bone implants. Inclusion of second phase reinforcements in HA such as carbon nanotubes (CNT) and graphene nanosheets is expected to significantly improve its mechanical properties. In this study, a computational framework that will improve the understanding of the mechanical behavior of graphene nanosheet and CNT-reinforced HA-nanocomposites is proposed. The variation of elastic modulus of HA-nanocomposites is assessed based on the nanofiller type, volume fraction, alignment, area, thickness, and aspect ratio using the finite element modeling. The results of the simulations show that graphene nanosheets are more effective in improving the elastic modulus of nanocomposites than CNTs at similar volume fractions. HA-nanocomposites reinforced by graphene nanosheets exhibit transversely isotropic material properties and provide the highest elastic modulus when aligned along a direction or randomly distributed in a plane, whereas CNTs provide the best reinforcement when aligned along an axis. Variation in graphene nanosheet area, thickness, aspect ratio, and carbon nanotube length have negligible effect on elastic modulus of the HA-nanocomposite. In addition, comparison between the finite element simulations and theoretical calculations show that clustering of nanoinclusions reduces the effectiveness of the reinforcement they provide. The simulation results and the computational framework presented in this study are expected to help in determining the best design and manufacturing parameters that can be adapted for developing HA-nanocomposite bone implant materials.

scholarly journals Hardening of Nickel Alloys by Ion Implantation of Titanium and Carbon

1996 ◽  
Vol 444 ◽  
Author(s):  
S. M. Myers ◽  
D. M. Follstaedt ◽  
J. A. Knapp ◽  
T. R. Christenson
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Surface Layer ◽  
Ion Implantation ◽  
Finite Element Modeling ◽  
Yield Stress ◽  
Nickel Alloys ◽  
Element Modeling ◽  
Order Of Magnitude ◽  
Amorphous Surface

AbstractDual ion implantation of titanium and carbon was shown to produce an amorphous surface layer in annealed bulk nickel, in electroformed Ni, and in electroformed Ni7 5Fe 2 5. Diamond-tip nanoindentation coupled with finite-element modeling quantified the elastic and plastic mechanical properties of the implanted region. The amorphized matrix, with a thickness of about 100 nm, has a yield stress of approximately 6 GP and an intrinsic hardness near 16 GPa, exceeding by an order of magnitude the corresponding values for annealed bulk Ni. Implications for micro-electromechanical systems are discussed.

scholarly journals Evaluating Mechanical Properties of Thin Layers using Nanoindentation and Finite-Element Modeling: Implanted Metals and Deposited Layers

1996 ◽  
Vol 438 ◽  
Author(s):  
J. A. Knapp ◽  
D. M. Follstaedt ◽  
J. C. Barbour ◽  
S. M. Myers ◽  
J. W. Ager ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Layer Thickness ◽  
Young's Modulus ◽  
Thin Layers ◽  
Element Modeling ◽  
Surface Modified

AbstractWe present a methodology based on finite-element modeling of nanoindentation data to extract reliable and accurate mechanical properties from thin, hard films and surface-modified layers on softer substrates. The method deduces the yield stress, Young's modulus, and hardness from indentations as deep as 50% of the layer thickness.

Computing Thin Film Mechanical Properties With the Oliver and Pharr Method

1999 ◽  
Vol 593 ◽  
Author(s):  
P.J. Wolff ◽  
B.N. Lucas ◽  
E.G. Herbert
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Dimensional Analysis ◽  
Film Properties ◽  
Element Modeling ◽  
Indentation Tests

ABSTRACTA commonly used technique to compute mechanical properties from indentation tests is the Oliver and Pharr method. Using dimensional analysis and finite element modeling, this paper investigates errors when the Oliver and Pharr method is used to compute thin film properties.

Hall–Petch relationship in pulsed-laser deposited nickel films

2004 ◽  
Vol 19 (1) ◽  
pp. 218-227 ◽  
Author(s):  
J.A. Knapp ◽  
D.M. Follstaedt
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Finite Element Modeling ◽  
Pulsed Laser ◽  
Fused Silica ◽  
Thin Layers ◽  
Element Modeling ◽  
Petch Relationship ◽  
Grain Sizes ◽  
Dislocation Movement

Thin-film mechanical properties can be measured using nanoindentation combined with detailed finite element modeling. This technique was used for a study of very fine grained Ni films, formed using pulsed-laser deposition on fused silica, sapphire, and Ni substrates. The grain sizes in the films were characterized by electron microscopy, and the mechanical properties were determined by ultra-low load indentation, analyzed using finite element modeling to separate the mechanical properties of the thin layers from those of the substrates. Some Ni films were deposited at high temperature or annealed after deposition to enlarge the grain sizes. The observed hardnesses and grain sizes in these thin Ni films are consistent with the empirical Hall–Petch relationship for grain sizes ranging from a few micrometers to as small as 10 nm, suggesting that deformation occurs preferentially by dislocation movement even in such nanometer-size grains.

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